I think most people who use JSON don't want strong typing or to use schemas. If you do, you just use a different serialization format: JSON is designed to be a generic, human-readable way to basically represent any kind of data structure (since it deserializes to JS objects). So everything about JSON is working against you if you do try to enforce type/schemas on it.
A grpc-like protocol with more prescriptive type registries/discovery (over the network) and better interop with http (like grpc-gateway) would be the best approach IMO. Definitely not JSON schema